(Comp.sys.handhelds)
Item: 2766 by NU123952 at VM1.NoDak.EDU
Author: [Mark A. Ordal]
  Subj: Bessel Yn(x) and Jn(x)
  Date: Sat Apr 13 1991

Here's my latest set of Bessel function programs for the HP-48.  The
only programs you need to call directly are Ynx and Jnx.  However, if
you are plotting something (e.g., the intensity of the diffraction pattern
of a circular aperature -- which involves J1) you might get a slight
speed improvement by directly calling the J1 program (named ASJ1).

The comments are pretty complete so just read through the listing
to see how to call the programs and see where I got the algorithms.

Note that BESSEL.SRC is the ASCII (translate 3) listing of a directory.
The separate programs can be adapted for use on a 28S.  In fact, most run
unchanged on the 28S.  For Ynx and Jnx, you have to replace the CASE
statement with nested IF statements.  The DECR command used in NRJN and
NRYN has to be replaced with 28S equivalents (the comments explain what to
do).

               Dr. Mark A. Ordal
               Physics Department
               North Dakota State University
               Fargo, ND 58105
               NU123952@NDSUVM1